Initiation and development of water film by seepage   总被引：1，自引：1，他引：0  

Xiaobing Lu  Peng Cui  Kaiheng Hu  Xuhui Zhang 《山地科学学报》2010,7(4):361-366

When water seeps upwards through a saturated soil layer,the soil layer may become instability and water films occur and develop.Water film serves as a natural sliding surface because of its very small friction.Accordingly,debris flow may happen.To investigate this phenomenon,a pseudothree-phase media is presented first.Then discontinuity method is used to analyze the expansion velocity of water film.Finally,perturbation method is used to analyze the case that a water flow is forced to seep upwards through the soil layer while the movement of the skeleton may be neglected relative to that of water.The theoretical evolutions of pore pressure gradient,effective stress,water velocity,the porosity and the eroded fine grains are obtained.It can be seen clearly that with the erosion and redeposited of fine grains,permeability at some positions in the soil layer becomes smaller and smaller and,the pore pressure gradient becomes bigger and bigger,while the effective stress becomes smaller and smaller.When the effective stress equals zero,e.f.liquefaction,the water film occurs.It is shown also that once a water film occurs,it will be expanded in a speed of U(t)(1-ε).  相似文献   

MSCT和X线平片在诊断腰椎滑脱症中的临床价值比较   总被引：3，自引：1，他引：2  

付传明  陈义加  陈学强  陈伦刚  邹建华  吴文强 《CT理论与应用研究》2010,19(3):67-73

目的:比较X线平片和多排螺旋CT诊断腰椎滑脱的准确性,并评价临床价值。方法:搜集40例经X线平片、MSCT检查诊断并手术治疗的腰椎滑脱患者,X线平片和MSCT判定腰椎滑脱程度、部位、类型的结果与手术对照。结果:40例患者,27例手术证实为真性滑脱,13例为假性滑脱。以手术为对照,X线平片、MSCT诊断腰椎滑脱程度和部位准确率为100%;X线平片判定腰椎滑脱类型的敏感性、特异性、阳性和阴性预测值为分别为59.3%、100%、100%和54.2%;MSCT判定滑脱类型的敏感性、特异性、阳性和阴性预测值均为100%;X线平片和MSCT对滑脱类型判定具有明显统计学差异(P0.01)。结论:X线平片、MSCT判定腰椎滑脱程度和部位均具有较高的准确性;判定腰椎滑脱类型,MSCT比X线平片好,X线平片目前仍是基本的筛查方法,MSCT进一步明确腰椎滑脱类型诊断,为临床提供更多的影像信息和治疗方案。  相似文献   

河南省洛宁上宫金矿复杂地层钻探施工技术          下载免费PDF全文

祁新堂  谢永德  刘梁  任飞飞 《探矿工程》2020,47(3):38-43

河南省洛宁上宫金矿区地质条件复杂,地层破碎,特别是中下部蚀变绿泥石化严重,遇水分散剥落坍塌,易造成下钻困难、埋钻等事故,施工难度大。针对矿区地层特点,从设备材料选型、钻孔结构、钻头选用等方面采取措施,重点应用成膜冲洗液解决蚀变破碎绿泥石化地层孔壁失稳取心钻进困难问题,取得了显著效果,为今后复杂地层施工积累了一定的经验。  相似文献   

调光生态膜光学性能研究   总被引：5，自引：2，他引：3  

苗洪利  林敬文  郑荣儿  彭凯平  赵建纲  孟继武 《中国海洋大学学报(自然科学版)》2005,35(2):335-338,266

为提高光合作用效率,促进农作物早熟、增产,根据叶绿素进行光合作用所需的吸收谱,采用新型有机共轭分子化合物按一定比例分散到聚烯烃化合物中,可产生与叶绿素吸收谱匹配的荧光谱,从而实现对太阳光谱中不同波段光的红移。对调光膜进行光学性能研究。结果表明：直射光透光率略低于普通膜,而散射光的透光率大于普通膜;红橙光波段调光度较高,蓝紫光波段的调光度较低;光学稳定性早期衰减较大,但逐渐趋于平稳。  相似文献   

照相透镜重镀增透膜及使用情况     

钟树华  张霄宇  陈学昆 《天文研究与技术》1998,(1)

介结了云南天文台太阳光谱仪１９８８年进行的重镀１１块照相透镜增透膜以及镀膜后的使用情况。重镀增透膜前照相透镜的透过率已降低到７７％～８４％,重镀后提高到９２％～９８％。相对于镀膜之前的透过率数值提高１４％～２６％,照相露光时间缩短１倍左右。  相似文献   

缓蚀剂浓度对饱和CO2盐溶液中咪唑啉缓蚀剂膜的影响   总被引：1，自引：0，他引：1  

杜敏  张静  王宁 《中国海洋大学学报(自然科学版)》2009,39(5)

咪唑啉及其衍生物是油田行业常用的耐二氧化碳腐蚀的缓蚀剂,其缓蚀机制主要是化学吸附作用。本文采用失重法、弱极化法、交流阻抗法等手段研究了1种新型咪唑啉缓蚀剂对Q235钢在饱和CO2盐溶液中不同浓度随时间的缓蚀行为变化,探讨了吸附膜的形成与衰减规律。结果表明:85℃存在极值浓度40 mg.L-1,此时缓蚀剂达到最佳状态,24 h即可成膜,膜寿命较长,可以维持至少120 h。  相似文献   

斜抽运无机液体激光器的流场热分布   总被引：1，自引：0，他引：1  

胡滔  魏泳涛  宋影松  张玉明  李密  马再如  冯国英 《海洋学报》2010,32(10):7027-7035

激光二极管斜抽运的多增益段串接的液体激光器能够明显地提高激光光束质量、获得较高的输出功率.针对斜抽运子增益段工作时所涉及的流动、传热和壁面耦合,建立了计算子增益段流场热分布的流-热-固耦合模型,应用有限单元法完成了其瞬态流场热分布的数值模拟.该方法排除了不精确的换热系数对计算结果的影响,使得换热系数不再是计算的先决条件,而只是计算结果之一;并且为评价流道形状、流速、吸收系数等因素对流场热的影响,以及进一步改进和控制液体激光介质的流场热分布,提供了可靠的分析方法.数值模拟研究表明:换热系数是空间位置的函数;  相似文献   

A dual sensor device to estimate fluid flow velocity at diffuse hydrothermal vents     

J. Sarrazin  P. Rodier  M.K. Tivey  H. Singh  A. Schultz  P.M. Sarradin 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2065-2074

Numerous attempts have been made over the last thirty years to estimate fluid flow rates at hydrothermal vents, either at the exit of black smoker chimneys or within diffuse flow areas. In this study, we combine two methods to accurately estimate fluid flow velocities at diffuse flow areas. While the first method uses a hot film anemometer that performs high-frequency measurements, the second allows a relatively rapid assessment of fluid flow velocity through video imagery and provides in situ data to calibrate the sensor. Measurements of flow velocities on hydrothermal diffuse flow areas were obtained on the Mid-Atlantic Ridge (MAR). They range from 1.1 to 4.9 mm/s at the substratum level, in low-temperature (4.5–16.4 °C) diffuse flow areas from the Tour Eiffel sulfide edifice. A strong correlation was observed between fluid flow velocities and temperature, supporting the possible use of temperature as a proxy to estimate the flow rates in diffuse flow areas where such a simple linear flow/temperature relation is shown to dominate.  相似文献   

Tunable surface-plasmon-resonance wavelength of silver island films     

王继飞  李宏建  周子游  李雪勇  刘菊  杨海艳 《海洋学报(英文版)》2010,29(11)

This paper experimentally and theoretically investigates the effect of the underlayer medium on tuning of the surface plasmon resonance (SPR) wavelength of silver island films, and the effect of substrate temperature on the morphologies and optical properties of the films. From the absorption spectra of single Ag with various thickness and overcoated (Ag/TiO₂) films deposited on glass substrates at various substrate temperatures by RF magnetron sputtering, we demonstrate that the surface plasmon resonance wavelength can be made tunable by changing the underlayer medium, the thickness of metal layer and the substrate temperature. By varying substrate temperatures, the interparticle coupling effects on plasmon resonances of nanosilver particles enhance as the spacing between the particles reduces. When the substrate temperature is up to 500 ℃, the absorption peak decreases sharply and shifts to shorter wavelength side due to the severe coalescence between silver islands in the film.  相似文献   

Thermal effect mechanism of magnetoresistance in p-type diamond films     

秦国平  孔春阳  阮海波  黄桂娟  崔玉亭  方亮 《海洋学报(英文版)》2010,29(11)

Based on the analysis and the discussion of the influence of thermal ionization energy and various scatterings on magnetoresistance(MR) of p-type diamond films, a revised model of valence band split-off over temperature is put forward, and a corresponding calculation formula is given for the MR of p-type diamond films (Corbino discs). It is shown that the theoretical calculation that the MR of diamond films changes with temperature is consistent with the experiment. The influence of Fermi energy level on MR of diamond films is discussed. Additionally, the thermal effect mechanism of MR in p-type diamond films is also explored.  相似文献